Troubles taking a 360 .060?

Buy “cheap pistons” meaning I’m thinking your investment in them is well under their actual cost new... as in the overall investment thus far in minimal.

You asked the cost. I own a certified tester, and know how to use it. I’ve tested for local shops before so I know what having to stand behind results can mean. Your reluctance is just a question of value to you. Is it worth it to spend 3-400 in order to make sure the other $6k delivers. Only you can determine that. Your interest in the question shows you’re asking the right questions.
That being said- you’re ignorant of a lot. That’s not a bad thing, just means there’s more to what you’re asking than what you’re asking. For instance- it won’t work on a swap meet block unless the block was just professionally cleaned, or just ran with bare iron walls. No oil, rust, dirt, or dust as all of those skew the readings. It also won’t work reliably with a cheap tester with preset frequencies. So if the tester you have can be calibrated to that particular iron (mine can) you’ll also need something to measure down to the thousandth with you too. Plus, a dependable test is not three spots on the major thrust. It takes me about 2 hrs to complete a test. 16-20 spots, plus four running scans for the thinnest in the four compass directions per hole.